Studies have been designed to elucidate the physiological and pharmacological responses of the ocular tissues to adrenergic neural activity and adrenergic drugs. Studies will be made primarily on conscious rabbits and monkeys and includes the following specific aims: (a) Correlation of the pupillary, intraocular pressure and cyclic AMP responses to the beta adrenergic agonist salbutomol prior to, and following administration of the beta adrenergic antagonist propranolol; (b) Determination of the interaction of the alpha and beta adrenergic agonists on intraocular pressure and cyclic AMP in the aqueous humor; (c) Elucidation of the adaptive response of the intraocular pressure to chronic treatment with catecholamines; (d) Further development of pneumatic procedures for the continuous recording of intraocular pressure in conscious animals, and for evaluation of aqueous humor dynamics by applanation tonography.